I have a super late model with no tags to tell me what kind it is the only numbers i found on the car is a 03 on a sqaure bar on the driverside floor board and was wondering if anyone could tell me about it

is it the # 55 car you had posted a week ago ? a true lefthander car would have a tag that says lefthander chassis on it with a 4 digit # on it. they started doing that in about 99 or so the earlier cars had a 4 digit # welded to the frame rails. some of the port citiy cars had #s welded to the ls fram rail also